Knowledge about the ontogeny of human development prior to birth, and the contribution of the prenatal period to postnatal life has been hampered by the lack of access to the fetus. The goals of this project are to document normal fetal development during the latter half of gestation; to investigate predictive relations from the fetus to the infant; and to elucidate the role of maternal psychophysiology on fetal and infant development. Seven hypotheses are proposed: (i) FHR reactivity increases over the second half of gestation, (ii) Fetuses can habituate to external stimulation and the rate will increase over gestation; (iii) Increased maternal stress is associated with decreased FHR variability, increased activity and greater reactivity; (iv) Fetal behavior will be affected by maternal physiological and psychological state (induced maternal stress will associate with increased FHR and disorganized patterns of fetal movement and state); (v) Fetuses of multiparous women will have accelerated fetal development; (vi) There will be neurobehavioral continuity between fetuses and infants; and (vii) Maternal stress effects will influence infant behavior. The conceptual orientation is that fetal neurobehavior reflects the maturational status of the nervous system, and that individual differences in neural regulatory capacity are manifested within the normal range at each gestational age. The project employs a longitudinal design at six gestational ages. A total of 120 subjects, stratified for parity, will be tested. At each visit fetal (HR, motor activity, behavior) and maternal (heart period, respiratory rate, etc) measures will be recorded simultaneously during 50 undisturbed minutes. Data will be digitized and processed with customized software. Maternal affective characteristics will be determined at the onset of the study and appraisal of daily stressors will be measured at each visit. Two other studies are embedded in the design. Fetal habituation will be tested at 20, 28 and 36 weeks by measuring FHR and ultrasonographic indices of fetal movement in response to a rattle. Manipulation of maternal state will be done at 24 and 32 weeks by engaging the women in a video game and testing with a phrase association task. Infants will be tested at 4 and 9 months on a variety of measures.